The present invention relates to mechanical ventilation systems. More particularly, it relates to mechanical respiratory assistance by ambient pressure control ventilation in a close chamber.
Assisted or artificial respiratory actions on patients are often used in medical practice. Two types of ventilation methods are generally used: positive pressure ventilation, when periodic positive airway pressure is applied on patients airways and lungs, and negative pressure ventilation (iron lungs) when the patient""s chest region is enclosed by an enclosure in which subatmospheric pressure is applied periodically.
Those main traditional methods of mechanical respiratory assistance such as positive airway pressure ventilation as well as xe2x80x9ciron-lungsxe2x80x9d are known to have a lot of physiological adverse effects, technical disadvantages and pitfalls. The main disadvantages of positive pressure methods of ventilation stem from the need to inflate the gas mixture into the patient""s airway and lungs with such a positive pressure that its range is comparable with right and left heart ventricles filling pressures. This can interfere with the venous blood return to the heart that may result in hemodynamic deterioration, especially in patients that suffer from hypovolemia, compromised cardiac function, lung and chest problems and shock. Furthermore, patient""s suffering from these diseases are already in poor medical condition, and their body is very likely not to withstand the strenuous procedure. Positive pressure ventilation may also result in barotrauma of airway and lungs with possible development of life threatening complications. Long time exposure to positive pressure ventilation may result also in the development of lung atelectasis and/or secondary infection, which is directly related to the duration of the mechanical positive pressure ventilation. Positive pressure ventilation also requires the inflation of endotracheal tube balloon with such pressures that on one hand, it establishes airway sealing, but on the other hand it may result in severe damage to the tracheal mucosa and tracheal wall, potentially leading to very dangerous complications, such as tracheal wall and great mediastinal vessels rupture.
Negative pressure ventilation, as opposed to positive pressure ventilation, is free from problems related to venous return and cardiovascular deterioration as well as barotrauma development. There are problems that arise from the employment of negative pressure ventilation. The need to accommodate the patient""s body in an enclosure requires the use of sealing means that are very difficult to fit on the patient""s neck, chest and abdomen. It is especially difficult in pediatric population or in uncooperative patients as well as during prolonged mechanical ventilation. Negative pressure ventilators are very difficult to use in weaning from mechanical ventilation.
Improvements of mechanical respiratory systems are known in the art. An example of such system that encloses the chest region is disclosed in U.S. Pat. No. 4,815,452 xe2x80x9cVENTILATOR APPARATUS AND FLUID CONTROL VALVExe2x80x9d, filed in 1988 by Z. Hayek. One aspect of the invention provides a patient enclosure for ventilator apparatus comprising a base member and a liftable cover member which in an operative position defines a patient receiving chamber having at least one aperture in the cover member for accommodating a portion of the patient""s body, the or each such aperture in the cover member being open along an edge of the cover member which overlies the base member in the operative position and containing a seal member for forming a substantially airtight seal in use between the cover member and the patient""s body and the base member, wherein the seal member takes the form of a flexible curtain having a free edge overlying the base member and means for tensioning a portion of the curtain to cause the curtain to seal against the base member and the patient""s body.
Another enclosure for ventilation is disclosed in EP patent No. 0379049 xe2x80x9cCHEST ENCLOSURE FOR VENTILATORSxe2x80x9d published in 1990 by Z. Hayek. This chest enclosure is used for introducing assisted ventilation for the lungs of a patient, when combined with an air oscillator. The chest enclosure comprises a stiff but flexible plastic tunnel member adapted to cover the chest, provided at its upper and its lower end with an air-impermeable flexible cushion, a band of flexible material extending from along the entire lateral edges of the tunnel, said bands extending to behind the back of the patient in an overlapping relationship, means being provided for the attachment of the bands with each other, an air passageway being provided into the enclosure for connection to an air oscillator.
Ventilators of this type provide an apparatus in which at least the patient""s head protrudes from the enclosure. In order to enable pressure changes in the enclosure, sealing the enclosure from the surrounding is necessary. Sealing the enclosure promotes problems and can also delay the commencing of assisted respiration, which potentially may cause damage to the patient.
The use of a pressurized container in which the whole body is enclosed was developed for blood oxygenation in premature neonates. The method is disclosed in U.S. Pat. No. 5,582,574 xe2x80x9cHYPERBARIC INCUBATION METHODxe2x80x9d filed in 1995 by F. S. Cramer. This pressurized container is filled with pure oxygen. The apparatus, and the method of treatment provided thereby, are able to deliver oxygen to the blood of an enclosed premature neonate by means of directly diffusing molecular oxygen through the unusually permeable skin of such infants. Hyperbaric pressure, i.e., pressure substantially above one atmosphere absolute (ATA), preferably at least two ATA, is maintained in the container, which facilitates the transcutaneous delivery of oxygen to the blood. Means are included for protecting the eyes of the neonate and for performing physiological ventilation of the lungs thereof. The provision of normal tissue oxygen tensions facilitates the neurological development of the infant, thereby enhancing its long-term quality of life.
It is a purpose of the present invention to provide new ambient pressure control ventilation apparatus for mechanical ventilation of a patient. The patient is placed inside a sealed chamber wherein within that chamber periodic changes of pressure are applied.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for mechanical ventilation applicable in cases were traditional mechanical ventilation fails. These cases include among others patients with hemodynamic deterioration such as hypovolemia, compromised cardiac function, marginal cases of respiratory distress syndrome, chest, airway and lung trauma and bleeding, and asthmatic attack.
Yet another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for home ventilation which is safer for users and provide more comfort conditions for patients suffering from chronic respiratory failure who need negative or positive pressure ventilators for home use, especially in pediatric and uncooperative populations.
Still another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for weaning from mechanical ventilation.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for patients with chest, neck and abdomen deformity, scars, chronic infections, burns etc., which make positive pressure ventilation difficult and negative pressure ventilation impossible.
Yet another purpose of the present invention is to provide an ambient pressure control ventilation apparatus for the treatment of patients suffering from congestive heart failure. The outpatient, home or intermittent overnight use of the novel apparatus enables decreasing at least part of the patient""s medication intake.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for patients having prophylactics of deep and superficial venous thrombosis that enables elimination of anticoagulation treatment.
It is another purpose of the present invention to provide an ambient pressure control ventilation apparatus for substitution of intraortic balloon counterpulsation (IABC) device.
Another purpose of the present invention aims at providing an ambient pressure control ventilation apparatus for substitution of advanced closed cardiac massage devices (Cardiopump, Four-phase Life-stick etc.).
It is thus provided an ambient pressure control ventilation apparatus for mechanical ventilation of a patient comprising:
a sealable chamber adapted to accommodate a whole body of a patient,
a pump fluidically connected to said chamber adapted to alternatively compress and decompress a ventilating gas within said chamber;
a relief valve, fluidically connected to said chamber; and
a control unit adapted to control said pump and said relief valve so as to facilitate a periodic regime of alternating compression and decompression of said ventilating gas within said chamber, about a predetermined baseline.
Furthermore, in accordance to another preferred embodiment of the present invention, said ventilating gas is a mixture of air and oxygen.
Furthermore, in accordance to another preferred embodiment of the present invention, said ventilating gas is oxygen.
Furthermore, in accordance to another preferred embodiment of the present invention, said apparatus further comprising at least one pressure sensor within said chamber, said at least one pressure sensor communicating with said control unit so as to allow said control unit to determine the pressure condition within said chamber.
Furthermore, in accordance to another preferred embodiment of the present invention, said control unit is further adapted to prevent oxygen partial pressure drop within said chamber below a predetermined pressure value.
Furthermore, in accordance to another preferred embodiment of the present invention, said predetermined pressure value is 0.25 atm.
Furthermore, in accordance to another preferred embodiment of the present invention, said baseline ranges between 0.5 atm. and 1.5 atm.
Furthermore, in accordance to another preferred embodiment of the present invention, said control unit is adapted to control said pump and said relief valve so as to facilitate a periodic regime of alternating compression and decompression of said ventilating gas within said chamber, about a predetermined baseline, within a predetermined pressure range of the baseline plus 170 mm Hg to the baseline minus 170 mm Hg.
Furthermore, in accordance to another preferred embodiment of the present invention, said control unit is adapted to control said pump and said relief valve so as to facilitate a periodic regime of alternating compression and decompression of said ventilating gas within said chamber, about a predetermined baseline, within a predetermined pressure range of between the ambient barometric pressure to the ambient barometric pressure plus 175 mm Hg.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is transportable.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is provided with wheels for transportation.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is essentially made of non-compliant transparent plastic material.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is provided with a door adapted to allow quick bringing in and taking out of a patient.
Furthermore, in accordance to another preferred embodiment of the present invention, said door can also be opened and closed from within said chamber.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is provided with a sealable opening adapted to allow quick access of a nursing team to the airway and chest area of said patient.
Furthermore, in accordance to another preferred embodiment of the present invention, a bed is provided in said chamber for the patient to lie on.
Furthermore, in accordance to another preferred embodiment of the is present invention, The apparatus as claimed in claim 1, wherein said chamber is provided with a communication block that is adapted to facilitate linking of devices positioned within said chamber to said control unit or other devices.
Furthermore, in accordance to another preferred embodiment of the present invention, monitoring lines from sensors placed in an endotracheal tube within the airway of the patient are connected via said communication block to said control unit.
Furthermore, in accordance to another preferred embodiment of the present invention, a reserve oxygen balloon is provided for emergency cases.
Furthermore, in accordance to another preferred embodiment of the present invention, said chamber is further provided with a highly compliant breathing bag that is designed to be connected to the airway of the patient.
Furthermore, in accordance to another preferred embodiment of the present invention, said pump is electrically connected to the main electric supply.
Furthermore, in accordance to another preferred embodiment of the present invention, a reserve battery adapted to supply electricity to said pump is provided for cases of emergency.
Furthermore, in accordance to another preferred embodiment of the present invention, there is provided an ambient pressure control ventilation method for mechanical ventilation of a patient comprising the following steps:
1. providing a sealable chamber adapted to accommodate a whole body of a patient;
2. providing a pump fluidically connected to said chamber adapted to alternatively compress and decompress a ventilating gas within said chamber;
3. providing a relief valve, fluidically connected to said chamber;
4. providing a control unit adapted to control said pump and said relief valve so as to facilitate a periodic regime of alternating compression and decompression of said ventilating gas within said chamber, about a predetermined baseline;
5. placing a whole body of a patient in said sealable chamber; and
6. providing a periodic regime of alternating compression and decompression of a ventilating gas within said chamber, about a predetermined baseline.
Furthermore, in accordance to another preferred embodiment of the present invention, said ventilating gas is a mixture of oxygen and air.
Furthermore, in accordance to another preferred embodiment of the present invention, said baseline ranges between 0.5 atm. and 1.5 atm.
Furthermore, in accordance to another preferred embodiment of the present invention, the periodic regime of alternating compression and decompression of said ventilating gas within said chamber alternates between said baseline plus 170 mm Hg to said baseline minus 170 mm Hg.
Furthermore, in accordance to another preferred embodiment of the present invention, the baseline is the ambient barometric pressure.
Furthermore, in accordance to another preferred embodiment of the present invention, the periodic regime of alternating compression and decompression of said ventilating gas within said chamber, alternates between the ambient barometric pressure to the ambient barometric pressure plus 175 mm Hg.
Furthermore, in accordance to another preferred embodiment of the present invention, the periodic regime of alternating compression and decompression of said ventilating gas within said chamber, alternates between the ambient barometric pressure minus 90 mm Hg to the ambient barometric pressure plus 90 mm Hg.
Furthermore, in accordance to another preferred embodiment of the present invention, said method further comprises the step of compressing into said chamber an additional volume of oxygen upon an oxygen partial pressure drop below a predetermined value within said chamber.
Finally, in accordance to another preferred embodiment of the present invention, said predetermined value is 0.25 atm.